Alert archive / Montana / Special Weather Statements in 2021

Special Weather Statement, NWS Great Falls, MT

August 8, 20215 counties in Montana

NWS Great Falls, MT issued this special weather statement at Aug 8, 2021, 2:37 PM MDT for 5 counties in Montana. It was in force for 83 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Aug 8, 2021, 2:37 PM MDT (20:37 UTC)
Expired: Aug 8, 2021, 4:00 PM MDT
In force: 83 min
Issued by: NWS Great Falls, MT
Hail: 0.00 in
Wind: 50

Counties Beaverhead County, MT, Broadwater County, MT, Gallatin County, MT, Jefferson County, MT, Madison County, MT

The radar

The Missoula radar (KMSX), 219 km from the middle of the area, began a volume at 20:40 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 8.6 hours before the alert went out and 260 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 16 J/kg
Mixed-layer CIN: -213 J/kg
Mixed-layer LCL: 2411 m above ground
0-6 km bulk shear: 47 kt
0-1 km storm-relative helicity: 81 m²/s²
0-3 km storm-relative helicity: 174 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

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What forecasters said that day

The local office's own words before this special weather statement went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Great Falls, MT wrote its last area forecast discussion before this special weather statement went out at Aug 8, 2:27 PM MDT, 10 minutes earlier.

Area forecast discussion, Aug 8, 2:27 PM MDT, 10 minutes before

Area Forecast Discussion
National Weather Service Great Falls MT
227 PM MDT Sun Aug 8 2021

.SYNOPSIS...
A strong cold front will continue to move eastward through the
region tonight. Expect a band of rain and thunderstorms to
accompany the cold front. Other than a few showers on Monday in
the Havre area, generally dry conditions are expected across the
area through the rest of the work week. Additionally,

&&

.DISCUSSION...
Tonight thru Monday...A strong cold front continues to move
eastward through the region. The most unstable air is generally
south of a line from Helena to White Sulphur Springs currently.
There is the potential that an isolated severe storm could develop
before 6 PM or so this evening, with the main threat being strong
wind gusts. Otherwise, the showers will generally decrease in all
areas by Midnight, except the Havre area, where it will continue
overnight. Overnight lows will get cold along the Rocky Mountain
Front and higher valleys of Southwest MT, with some locations
going below freezing. On Monday, expect scattered showers to be
slow to exit the Havre area, otherwise, the reminder of the region
will generally be dry, along with below normal temperatures.

Tuesday through Sunday...Expect a significant warming trend to
begin on Tuesday, with afternoon highs likely in the 90s by late
in the week or next weekend. Very little precipitation is expected
during the week, with a small potential for a few isolated
thunderstorms mainly on Friday and next Sunday. Note, kept
temperatures close to NBM, but did not go as high as the GFS per
it model error of high temperatures in urban areas. Brusda

&&

.AVIATION...
1150 AM MDT Sun Aug 8 2021 (08/18Z TAF period)

Main concern is the cold front moving from west to east across the
region this afternoon. IFR conditions are likely along the front,
along with areas of rain, especially over Central/North Central MT.
Some storms are also possible, some with brief strong wind gusts.
Conditions slowly improve after 06z tonight, but a few showers will
linger in the Havre area through 18z Monday. Some smoke moving into
Southwest MT, but overall visibility generally better than P6SM.
Mountains/passes will be obscured at times by clouds or smoke
through 12z Monday. Brusda

Refer to weather.gov/zlc for more detailed regional aviation weather
and hazard information.

&&

.FIRE WEATHER...
The Red Flag Warning will continue for fire weather zone 118.
A cold front is moving through the zone now, with gusty winds and
lightning the main threat. Conditions should improve early this
evening as a wetting rain develops.

Looking ahead, expect mostly dry conditions and very warm
temperatures by later in the week. Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  46  72  51  85 /  90  40   0   0
CTB  46  71  51  81 /  90  50   0   0
HLN  48  77  52  86 /  90  10   0   0
BZN  45  75  44  85 /  90  10   0   0
WYS  38  69  33  76 /  50   0   0   0
DLN  41  73  43  83 /  30   0   0   0
HVR  51  68  51  82 /  90  70  10   0
LWT  46  67  49  81 / 100  30   0   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until midnight MDT tonight Gallatin National
Forest.

Red Flag Warning until 9 PM MDT this evening Deerlodge/Western
Beaverhead National Forest...Helena and Townsend Ranger
Districts of the Helena National Forest.

Red Flag Warning until 9 PM MDT this evening Eastern Beaverhead
National Forest.

&&

http://www.weather.gov/greatfalls

In the hours before

Local storm report, Aug 8, 10:13 AM MDT, 4 hours 24 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
1013 AM MDT SUN AUG 8 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0945 AM     HEAVY RAIN       22 WNW BABB             48.96N 113.89W
08/08/2021  M1.28 INCH       GLACIER            MT   MESONET

            MESONET STATION GTOM8 19.7 NW LOGAN PASS.

0921 AM     HEAVY RAIN       8 SE EAST GLACIER PARK  48.36N 113.11W
08/08/2021  M0.72 INCH       GLACIER            MT   MESONET

            MESONET STATION DCRM8 DEEP CREEK RAWS.

0911 AM     HEAVY RAIN       SAINT MARY              48.74N 113.43W
08/08/2021  M0.70 INCH       GLACIER            MT   MESONET

            MESONET STATION SRYM8 SAINT MARY RAWS.

0930 AM     HEAVY RAIN       11 SW EAST GLACIER PARK 48.32N 113.35W
08/08/2021  M0.66 INCH       GLACIER            MT   MESONET

            MESONET STATION SUMM8 5.2 NE BLACKTAIL -
            RAILROAD ID.

0900 AM     HEAVY RAIN       4 NNW AUGUSTA           47.55N 112.43W
08/08/2021  M0.61 INCH       LEWIS AND CLARK    MT   MESONET

            MESONET STATION WLLM8 4.1 NW AUGUSTA.

0900 AM     HEAVY RAIN       5 SE BROWNING           48.51N 112.93W
08/08/2021  M0.51 INCH       GLACIER            MT   MESONET

            MESONET STATION SHBM8 5.2 SE BROWNING.

&&

Special weather statement, Aug 8, 1:26 PM MDT, 1 hour 11 minutes before

Special Weather Statement
National Weather Service Great Falls MT
126 PM MDT Sun Aug 8 2021

MTZ008-014-015-052>055-082045-
Broadwater MT-Madison MT-Beaverhead MT-Jefferson MT-Gallatin MT-
Central and Southern Lewis and Clark MT-Meagher MT-
126 PM MDT Sun Aug 8 2021

...Strong gusty wind threat will increase through the afternoon
across portions of Lewis and Clark, Broadwater, Meagher, Madison,
Beaverhead, Jefferson, and Gallatin Counties...

At 122 PM MDT, Doppler radar was tracking thunderstorms developing
across the area and generally moving east. Wind gusts of around 40
mph will be common with these storms. Isolated to scattered wind
gusts of 50 to 55 mph may also occur.

HAZARD...Wind gusts of 50 to 55 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Bozeman, Helena, Dillon, Townsend, West Yellowstone, Boulder, White
Sulphur Springs, Sheridan, Virginia City, Henrys Lake, Lincoln,
Belgrade, East Helena, Three Forks, Manhattan, Whitehall, Ennis, Twin
Bridges, Lima and Pony.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

If on or near area lakes, get out of the water and move indoors or
inside a vehicle. Remember, lightning can strike out to 10 miles
from the parent thunderstorm. If you can hear thunder, you are close
enough to be struck by lightning. Move to safe shelter now! Do not
be caught on the water in a thunderstorm.

Persons in campgrounds should consider seeking sturdy shelter until
these storms pass.

&&

LAT...LON 4436 11285 4569 11394 4594 11351 4576 11339
      4563 11270 4575 11219 4623 11260 4662 11230
      4684 11280 4712 11279 4713 11183 4691 11179
      4705 11111 4670 11027 4619 11028 4619 11078
      4449 11110 4475 11139 4454 11148 4457 11229
TIME...MOT...LOC 1922Z 294DEG 42KT 4675 11242 4515 11354

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...55 MPH

HART

Special weather statement, Aug 8, 2:37 PM MDT, 0 minutes before

Special Weather Statement
National Weather Service Great Falls MT
237 PM MDT Sun Aug 8 2021

MTZ008-015-052-053-055-082200-
Broadwater MT-Madison MT-Beaverhead MT-Jefferson MT-Gallatin MT-
237 PM MDT Sun Aug 8 2021

...Strong gusty wind threat continues this afternoon across
Broadwater, Madison, Beaverhead, Jefferson and Gallatin Counties...

At 234 PM MDT, Doppler radar was tracking thunderstorms across the
area which were generally moving east. Wind gusts of around 40 mph
will be common with these storms. Isolated to scattered wind gusts
around 50 mph may also occur.

HAZARD...Wind gusts up to 50 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Bozeman, Dillon, Townsend, Boulder, Sheridan, Virginia City, Henrys
Lake, Belgrade, Three Forks, Manhattan, Whitehall, Ennis, Twin
Bridges, Lima, Jackson, Pony, Monida, Wisdom, Alder and Silver Star.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

If on or near area lakes, get out of the water and move indoors or
inside a vehicle. Remember, lightning can strike out to 10 miles
from the parent thunderstorm. If you can hear thunder, you are close
enough to be struck by lightning. Move to safe shelter now! Do not
be caught on the water in a thunderstorm.

Persons in campgrounds should consider seeking sturdy shelter until
these storms pass.

&&

LAT...LON 4477 11313 4487 11346 4575 11392 4594 11351
      4576 11339 4588 11310 4563 11270 4575 11220
      4630 11257 4657 11165 4677 11150 4620 11106
      4619 11078 4505 11115 4449 11110 4475 11139
      4454 11148 4457 11229 4436 11285
TIME...MOT...LOC 2034Z 257DEG 22KT 4686 11145 4508 11349

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...50 MPH

HART

The office that day

Everything else NWS Great Falls, MT issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 8, 1:26 PM MDT	Special Weather Statement	TFX	Beaverhead, Broadwater, Gallatin, Jefferson, Madison, Meagher	79 min
Aug 8, 2:46 PM MDT	Special Weather Statement	TFX	Cascade, Judith Basin, Meagher	59 min
Aug 8, 3:09 PM MDT	Areal Flood Advisory	TFX	Cascade	51 min
Aug 8, 3:31 PM MDT	Special Weather Statement	TFX	Fergus, Judith Basin, Meagher	59 min
Aug 8, 4:03 PM MDT	Special Weather Statement	TFX	Beaverhead, Gallatin, Madison, Meagher	57 min
Aug 8, 4:29 PM MDT	Severe Thunderstorm Warning	TFX	Beaverhead, Gallatin, Madison	61 min

Nearby

Special Weather Statements in Montana, 2021 Every special weather statement in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.